Weapons Law Encyclopedia

Incendiary weapons

The use of fire as a weapon has a long history, and early incendiary weapons, like incendiary arrows, early firebombs and flamethrowers, dominated the battlefield for centuries until the introduction of gunpowder in the 15th century. The German army added flamethrowers to its arsenal in the 1914–18 War and by the end of the 1930s, hand-held and vehicle-mounted flamethrowers were in widespread military use on all sides. During the inter-war period, incendiary weapons were used by Italy in Ethiopia, as well as in the Spanish civil war and the Sino-Japanese war. The Geneva Disarmament Conference of 1932-1933 gave considerable attention to the question of incendiary weapons. The Draft Disarmament Convention presented at the end of the conference (never adopted in legally binding form) would have explicitly forbidden the use of projectiles specifically intended to cause fire, and appliances designed to attack persons by fire.For more detail, see, SIPRI, The Law of War and Dubious Weapons, 1976.

The 1939–45 War saw large-scale use of air-delivered incendiary weapons in population centres. In 1944, the Soviet Air Force dropped tons of incendiary bombs on Helsinki, and the Allied forces dropped the first napalm bombs on Tinian Island. Several tens of thousands of tons of bombs, mostly incendiary bombs, were subsequently dropped on cities and towns in Japan, causing immense devastation and massive loss of live. The bombing of Tokyo with incendiary weapons incinerated more people than the nuclear bombing of Hiroshima. German populations also suffered heavily from the use of incendiary weapons. The air raids on Hamburg (1943) and Dresden (1945) resulted in huge firestorms that consumed large parts of these cities.For more information, see, e.g., SIPRI, Incendiary Weapons, 1975, 30-40.

During the Cold War period, incendiary weapons were widely used in Algeria, Cambodia, Indo-China, Korea, the Sinai, Vietnam and elsewhere.See, e.g. SIPRI, Incendiary Weapons, 1975, 40-69; Human Rights Watch, Memorandum to Convention on Conventional Weapons Delegates: The Human Suffering Caused by Incendiary Munitions, March 2011. Pulitzer Prize winning photograph of Phan Thi Kim Phuc taken by Associated Press photographer Nick Ut (1972), following the bombing of the Vietnamese village Trang Bang has become emblematic of the extreme suffering and terrible impact on civilians caused by incendiary weapons.

During the 1970s, there was growing interest in addressing harm from the use of certain conventional weapons, most notably napalm and other incendiary weapons. Several initiatives dealt with this issue. The first suggestion within the United Nations that the use of napalm might be banned was contained in a report of the Secretary-General prepared in pursuance of a request by the General Assembly in its resolution 2444(XXIII). In 1972, the General Assembly adopted a resolution characterising incendiary weapons as ‘a category of arms viewed with horror’, and in 1973, the United Nations Secretary-General issued a detailed report on ‘Napalm and other Incendiary Weapons and all Aspects of their Possible Use’, which called for the prohibition of napalm and other incendiary weapons.UN General Assembly Resolution 2932 (XXVII) of 29 November 1972; Napalm and other Incendiary Weapons and all Aspects of their Possible Use:  Report of the Secretary-General; UN doc. A/8803/Rev. 1, 1973. For a more detailed overview of diplomatic initiatives dealing with napalm and other incendiary weapons in the early 1970s, see Department of Political and Security Council Affairs, The United Nations and Disarmament 1970-1975, United Nations, New York, 1976, Chapter X.

Since then, incendiary weapons have allegedly been used, albeit on a smaller scale, by several states and non-state actors, including within concentrations of civilians, for instance:

  • by Krajina Serb forces in Bihać​, Bosnia and Herzegovina, (1994).UN doc. S/PRST/1994/69; U.N. Doc. E/CN.4/1995/89 (1995) 8 March 1995.
  • by Turkey in Iraq (1991).C. Hedges, 'Iraqis are Arming the Rebel Kurds in Turkey's South', The New York Times, 20 October 1991; R. Gurdilek, 'Turkish Attacks in Northern Iraq; Kurds Claim Civilian Villages Hit', AP News Archive, 26 October 1991.
  • by Russian forces in Chechnya (1999).P. Felgenhauer, 'Russian Strategy in the Chechnya Wars', Parameter bewaffneter Konflikte, 2000.
  • by the USA in Iraq (2003 and 2004). Although it was initially denied, the USA later admitted having used a napalm-like incendiary weapon during the Persian Gulf War in Iraq (2003).See, 'Fire Bombs in Iraq: Napalm By Any Other Name', Iraq Analysis Group, March 2005, updated April 2005. In 2004, US forces allegedly used artillery shells loaded with white phosphorous in Fallujah, Iraq, to target insurgents in so-called ‘shake and bake’ fire missions.See, 'US: Incendiary weapon used in Iraq', Al Jazeera, 16 November 2005; D. Hambling, 'U.S. Denies Incendiary Weapon Use in Afghanistan', Wired: Danger Room, 15 May 2009.
  • by the USA and the Taliban in Afghanistan. According to media reports, the USA deployed an incendiary weapon to Afghanistan.See, D. Hambling, 'U.S. Denies Incendiary Weapon Use in Afghanistan', Wired: Danger Room, 15 May 2009. There are unconfirmed allegations that the USA also used incendiary weapons in Afghanistan. See, Human Rights Watch, White phosphorous: the New Napalm?, 8 June 2011.
  • by Ethiopian forces in Mogadishu, Somalia (2007).UN doc. S/2007/436, §§30–4.
  • by Israel in Lebanon (2006) and in Gaza (2009).UN doc. A/HRC/3/2, §§258–62; UN doc. S/2009/537, §§9, 207 and 488: ‘The Committee is, however, satisfied on the available evidence that white phosphorous was used as an incendiary weapon in densely populated areas.’
  • by Palestinian armed groups in Israel (2011).UN doc. S/2010/483 of 17 September 2010; Human Rights Watch, Memorandum to Convention on Conventional Weapons Delegates: The Human Suffering Caused by Incendiary Munitions, March 2011.
  • by Syrian armed forces in Syria (2012/2013). There have been allegations that Syrian armed forces air-dropped incendiary weapons, including incendiary cluster munitions and improvised ‘barrel bombs’, into concentrations of civilians.US State Department spokesperson Victoria Nuland affirmed that ‘the barrel bombs were “incendiary bombs which contain flammable material that can be like napalm' or can be packed with nails and launched from the air or from a launcher.’ ‘Syria army using missiles, barrel bombs’, News24, 13 December 2012. See, in particular, 'First Evidence Of Incendiary Submunition Cluster Bombs Used in Syria', Brown Moses Blog, 21 November 2012; Human Rights Watch, Syria: Incendiary Weapons Used in Populated Areas, 12 December 2012.
  • in Ukraine (2014). According to Human Rights Watch incendiary weapons were allegedly used in Ilovaisk and in Luhanskoe in July and August 2014.Human Rights Watch and International Human Rights Clinic (IHRC) at Harvard Law School, Incendiary Weapons: Recent Use and Growing Opposition Memorandum to Convention on Conventional Weapons Delegates, November 2014.​ HRW also reported that an abandoned firing position with several misfired 122mm Grad 9M22S rockets equipped with a 9N510 incendiary warhead was discovered in a field near Ilovaisk. The warhead contains 180 hexagonal incendiary capsules, which burn for two minutes. (Y. Lyamin and M. Smallwood, ‘9M22S Incendiary Rocket Components Documented in Eastern Ukraine’, The Hoplite, Armament Research Services, 14 October 2014.)
  • and by Russia in Syria (2016).M. Wareham, Dispatches: Incendiary Weapons Pose Civilian Threat in Syria, Human Rights Watch, 21 June 2016. Russian state-run television reportedly released video footage showing incendiary weapons, specifically, RBK-500 ZAB-2.5SM bombs, being loaded on a Su-34 fighter-ground attack aircraft. The use of incendiary weapons by Russia was confirmed by Russia’s Minister of Foreign Affairs, Sergey Lavrov, in a letter to Human Rights Watch. Lavrov attributed the ‘significant humanitarian damage’ caused by incendiary weapons in Syria to their ‘improper use’.

Last updated on: 04 August 2017

Incendiary weapons can be portable or mechanized, and they can be used with different weapon platforms. They include such diverse weapons as flamethrowers, incendiary grenades, landmines and fougasses The term ‘fougasse’ describes a variety of devices that are usually buried in the ground, are set off from a distance and project debris or flame in the direction of an enemy. Flame fougasses can act like flame throwers or incendiary mines. See, for example, Intelligence Bulletin, vol. III, no. 3, 1944, p. 80., air-dropped unitary ‘firebombs’, incendiary cluster munitions, incendiary rockets, incendiary artillery or mortar shells, incendiary naval ordnance, as well as improvised incendiary devices, for example, ‘Molotov cocktails’. Over 180 models of incendiary weapons currently exist.HRW, Memorandum to Convention on Conventional Weapons Delegates: The Human Suffering Caused by Incendiary Munitions, March 2011, citing Jane’s Ammunition Handbook 2007-2008. For an overview of incendiary weapons used in World War I and World War II, see SIPRI, Incendiary Weapons, 1975, pp. 75-80. For a proposal on possible ways of classifying incendiary munitions with a view to legal regulation, see ICRC, Report, Conference of Government Experts on the Use of Certain Conventional Weapons (Lucerne, 24.9-18.10.1974), Geneva, 1975, p. 106.

Types of incendiary agents used in incendiary weapons include:

  • Magnesium is a common metal incendiary. It can produce very high burning temperatures. In contact with burning magnesium, water may produce an explosive mixture of hydrogen and other gases, which renders fire-fighting measures very complicated. When magnesium particles react with moisture in the human body it can lead to further tissue necrosis.
  • Thermite, a mixture of powdered aluminium metal and ferric oxide, is a pyrotechnic incendiary. Thermite can produce temperatures of over 2000 degrees Celsius and can scatter small drops of molten metal, which may prolong and extend the incendiary effect, and can cause multiple deep burns.
  • Napalm is perhaps the most notorious oil-based incendiary substance. Napalm was originally a mixture of napthenic and palmitic acids, developed at Harvard University in 1942-43. Napalm compositions had a higher viscosity than earlier oil-based incendiary substances. It could be spread further and burned more slowly but at a higher temperature. This increased the likelihood of secondary fires. Napalm is not self-igniting, and is hence often combined with phosphorous. Napalm was widely used in World War II in flamethrowers and air-dropped bombs. Subsequently, napalm was used as a generic term to refer to incendiary compositions developed later, although these actually contain different chemical components. So-called Incendergel, Napalm-B or NP2 for instance, consist of a mixture of benzene, gasoline and polystyrene. These compositions burned longer, at somewhat higher temperature, and could be spread over wider areas. Such incendiary compositions tend to stick even to vertical surfaces and are almost impossible to remove.
  • White phosphorous is probably the most important pyrophoric incendiary. It ignites spontaneously in contact with atmospheric oxygen and continues to burn while exposed to oxygen until it is depleted or oxygen supply is cut off. The chemical reaction creates heat of around 815 degrees Celsius, as well as light and thick white smoke. This makes white phosphorous useful for creating smokescreens, illuminating areas, marking and signalling, providing tracers for ammunition, as well as for detonating mines, fuel supplies and ammunition caches. White phosphorous is not an effective incendiary substance for use against structures that are difficult to ignite, but it has been used against persons and to ignite oil-based incendiaries.
  • Triethylaluminium (TEA) is also pyrophoric and, in addition, reacts violently with water. It can produce temperatures of up to 2300 degrees Celsius, but burns very rapidly, making it unsuitable for use against materiel. Thickened TEA compositions (TPA) are used in small incendiary rockets designed to replace flamethrowers. The thermal radiation is said to be akin to a ‘fireball’ and being capable of inflicting full thickness (third degree) burns to a person in a bunker even without direct contact with the substance.For more detailed descriptions, see, SIPRI, Incendiary Weapons, 1975.

Mark-77 (Mk-77) type air-dropped unitary bombs are the primary incendiary bombs in active service in the US armed forces. Bombs of this type were reportedly used by the USA in Iraq and allegedly also in Afghanistan. These bombs are an evolution of the incendiary bombs M-47 and M-74, used during the Korea and Vietnam wars. In contrast to these older weapons, the filling of newer Mk-77 type bombs is composed of a polystyrene-like gel and kerosene-based jet fuel. The container is cigar-shaped and lightweight, made of aluminium. When the bomb is released from the aircraft, the container will tumble end over end, the arming wires are pulled from the fuzes, arming the bomb. When the bomb detonates, the container will rupture, disbursing the fuel gel mixture, which is then ignited.

Incendiary cluster submunitions, for instance, the US M-69 or the Soviet ZAB-25 were developed early in the 1939–45 War and used in huge numbers by the USA in fire raids on Japanese cities.For more types of US incendiary submunitions, see A. Parsch, BAK to BSU/BSG - Equipment Listing; G. Goebel, Incendiary Bombs/ Runway Breakers / Electonic Attack Weapons. A more recent US incendiary submunition is the M74A1. An M35 cluster munition can disperse 57 such incendiary submunitions.

Incendiary weapons of the Russian ZAB series have reportedly been used in Syria in 2012/2013. Among them the RBK-250 ZAB-2.5 bomb containing 48 ZAB-2.5 submunitions, the ZAB-100-105 and the ZAB-500 unitary bomb. The ZAB-100-105 may be found with a solid incendiary filling material or can be filled with small Incendiary bomblets which are scattered by the high-explosive bursting charge. N.R. Jenzen-Jones, 'ZAB-100-105 Incendiary Bomby in Syria', The Rogue Adventurer, 24 December 2012.

Flamethrowers, widely used in the first and second world war and in the Korea and Vietnam wars, have not been in the US arsenal since 1978. The US M202A1 ‘Flame Assault Shoulder Weapon’ (FLASH) was developed to replace flamethrowers, producing the same type of effects but with greater range and accuracy. It is a four-barreled bazooka firing M74 rockets equipped with M235 warheads, containing approximately 1.34 pounds (0.61 kg) of thickened pyrophoric agent (TPA), a liquid which spontaneously combusts in air and burns at high temperature. On impact a rocket scatters burning incendiary over a twenty-meter radius.

Used for similar purposes, the Russian ‘Shmel’ is a single-shot, man-portable, shoulder-launched rocket weapon system intended for dismounted infantryman that can fire RPO-Z incendiary rounds, as well as a fuel-air explosive round (RPO-A) and a smoke round (RPO-D).

The US AN-M14 incendiary hand grenade contains a thermate mixture that generates heat to 4000 degrees Fahrenheit. The grenade filler will burn from 30 to 45 seconds. The grenade body is of thin sheet metal and is cylindrical in shape.

Last updated on: 04 August 2017

Incendiary weapons work through a powerful exothermic (heat-producing) reaction typically involving oxygen in the surrounding air (or an oxidizing agent) and some sort of incendiary substance such as magnesium, napalm, thermite, triethylaluminium or white phosphorous. The combustion process can produce and sustain very high temperatures. The intense heat can melt metal structures and degrade non-flammable materials. In addition, the heat ignites secondary fires in flammable materials, like wood, plastics or asphalt. The combustion process rapidly retrieves the oxygen from the surrounding air and replaces it with carbon monoxide (CO). Under certain conditions, fires can coalesce into a ‘massfire’ or ‘firestorm’ characterized by hurricane strong winds and extremely high temperatures.

Incendiary weapons are designed to damage materials by fire and heat, and to cause burn or respiratory injury to persons. Besides these physical effects, military use of incendiary weapons can also aim to ahve psychological effects, operating on the basis that human beings experience strong fear of fire.ICRC, Weapons that may Cause Unnecessary Suffering or have Indiscriminate Effects, Report on the Work of Experts, 1972, paragraph 203: ‘The firebomb  is  also  an  antipersonnel  weapon,  and  because  of its  area effectiveness  and its  psychological  impact it has proved exceedingly  efficient’; A. Buncombe, ‘US admits it used napalm bombs in Iraq’, Independent, 10 August 2003: ‘The generals love napalm. It has a big psychological effect.’; N.T. Perkkio, Bring on the Flamethrower, 8 February 2005:‘Besides causing death and destruction, the flamethrower can greatly impact an enemy psychologically.’

Incendiary weapons are effective against fortified positions, armoured vehicles and dug-in emplacements. As the incendiary component can penetrate within targets, they can be used to drive out enemy soldiers from defensive positions.They can also be used to burn down vegetation providing cover for enemy forces.‘The greatest advantage of the flamethrower is it ability to penetrate small openings and fill fortified positions with both fire and smoke. Thus, the enemy either burns or asphyxiates due to the lack of oxygen available to breath. In the urban environment, the flamethrower can shoot fire around corners to enhance movement past dead or blind angles.’ N.T. Perkkio, Bring on the Flamethrower, 8 February 2005.

Incendiary bombs or shells are often described as area weapons, because they are ‘effective over a broad area, whether they are used against point targets or area targets’. The area effect may be due to the dispersal of the incendiary substance over an area or the self-propagating character of secondary fires.ICRC, Weapons that may Cause Unnecessary Suffering or have Indiscriminate Effects, Report on the Work of Experts, 1972, §§199 and 222; See also §56.


Incendiary weapons cause severe injury, including through thermal and chemical burns, pulmonary damage due to the inhalation of smoke and toxic fumes, circulatory shock, heat stroke, asphyxiation, and carbon monoxide poisoning. These effects are often fatal. Victims who survive suffer intense pain, severe infections, organ failure, and have lower resistance to disease. Injuries can result in lifelong deformity and disability, and often psychological trauma.

Severe burn injuries are extremely painful and require immediate, specialized and intensive medical care. The severity of the burn wounds depends on the depth of the burn (the degree) and the extent of the body surface area affected. Metal incendiaries burn at very high temperatures and have a tendency to splatter small particles of molten or burning metal onto the victims. This can cause multiple small but deep burns. Tissue destruction may be increased by the reaction of the incendiary, e.g. magnesium, with moisture in the body. Napalm-type incendiaries stick to and burn hot on the human body for an extended time (10-15 minutes), leading to extensive burns prone to infection. Even partial thickness (second degree) burns from napalm on a relatively small percentage of the skin can cause shock.Report of the Secretary-General, ‘Napalm and Other Incendiary Weapons and all Aspects of Their Possible Use’, UN doc. A/8803/Rev. 1, 1973; SIPRI, Incendiary Weapons, 1975, 152.

Certain incendiary substances are toxic. Failure to remove them from the body may have fatal consequences. White phosphorous, for instance, is highly soluble in fat, and thus in human flesh. If white phosphorus enters the bloodstream it can cause multiple organ failure. For this reason, burns on only 10% of the body are often fatal.Human Rights Watch, 'Memorandum to Convention on Conventional Weapons Delegates: The Human Suffering Caused by Incendiary Munitions', March 2011; SIPRI, Incendiary Weapons, 1975, 198 and Appendix 4A.

The burning of the incendiary substance and secondary fire consume oxygen from the surrounding air and emit large quantities of carbon monoxide. As a consequence, people in the vicinity may suffer respiratory injury from the inhalation of noxious gases. They may lose consciousness and can die from heatstroke, pulmonary burns and carbon monoxide poisoning, or from asphyxiation. The effects of heat and carbon monoxide poisoning are particularly important causes of mortality in large-scale fires resulting from incendiary attacks.

The treatment of burn victims is difficult, prolonged and intensely painful, at times involving multiple surgeries. The resources necessary to effectively treat severe burn injury are rare in many countries and likely to be inaccessible in times of armed conflict. Burns sustained in times of war are associated with high early mortality, but in many cases death may not ensue for days or even weeks of great suffering.SIPRI, Incendiary Weapons, 1975, 135-6. Certain incendiary substances, like white phosphorous, cannot easily be extinguished and present particular problems of treatment. White phosphorous particles projected by an explosive weapon can penetrate deep into soft tissue. Within the human body, it can burn for hours and tends to cause small, deep lesions. Victims and medical professionals who try to remove it may inadvertently spread the burning material to other areas of the body, in particular the hands. Wounds that have been cleaned and dressed can reignite again when dressings are removed. White phosphorous wounds are very slow to heal.

When incendiary weapons are used in conjunction with explosive weapons, victims may suffer combined burn and blast injury, which are associated with higher mortality than each wounding type alone. Mortality from incendiary weapons will also be affected by the state of health and nutrition of the affected population, and the limited resources to treat burn injuries.

Certain incendiary substances, like white phosphorous, can continue to burn in contact with oxygen for several days after their dispersal, and thereby pose a continuing health risk.Human Rights Watch, Rain of Fire, 2009, documents cases of civilians who were inured from stepping on white phosphorus remains up to 12 days after major hostilities had ended.

Survivors can suffer long-term respiratory problems from the effects of carbon monoxide poisoning. Severe burn wounds usually result in disability even after the wound has healed. Victims may experience loss of motor function due to the damage to muscles and scarring. Scars and other alterations of the physical appearance, the trauma from the severe injury and the painful and prolonged treatment, often involving isolation, can have serious psychological effects in the long-term, and can lead to withdrawal from society.

Material damage

The incendiary weapon itself and fires ignited by it can cause massive devastation to private property and public infrastructure. The spread of fire is difficult to predict and contain. Large-scale fires are difficult to fight. Under certain conditions large-scale fires can coalesce into a firestorm, associated with extremely high temperatures and hurricane strong winds, which is beyond the capacity of fire-fighters to control. A firestorm consumes all combustible matter within the affected area. People within this area, even those in underground shelters, are highly likely to die, either from the extreme heat or by asphyxiation.US air-raids with incendiary weapons on Japanese population centers killed 260,000 people and injured another 412,000.  Nearly two and a quarter million homes were destroyed and 9.2 million people left homeless. ICRC, Weapons that may Cause Unnecessary Suffering or have Indiscriminate Effects, Report on the Work of Experts, 1972, §206.

Environmental and societal impacts

Extensive destruction of homes, productive assets, food stocks, and public infrastructure following use of incendiary weapons can have wide-spread and long-lasting impacts on the well-being and survival of populations beyond those directly affected. Recent studies suggest that soot and ash lofted into the atmosphere as a result of large-scale fires and firestorms could impact regional weather and the climate.See, for example, O. B. Toon et al., 'Atmospheric effects and societal consequences of regional scale nuclear conflicts and acts of individual nuclear terrorism', in Atmos. Chem. Phys., 7, 1973–2002, 2007, 1989-99.

Last updated on: 04 August 2017

  • Incendiary bombs are dropped by U.S. Army Air Forces on Kobe, Japan, 4 June, 1945.

    Incendiary bombs are dropped by U.S. Army Air Forces on Kobe, Japan, 4 June, 1945.

    Source: USAF.

  • U.S. soldier of the 33rd Infantry Division using a flamethrower.

    U.S. soldier of the 33rd Infantry Division using a flamethrower.

    Source: 33rd Infantry Division Association.

Applicable international, regional & national law

1980 Convention on Certain Conventional Weapons

The 1980 Conventional Weapons Convention (CCW), also known as the Inhumane Weapons Convention, is an umbrella convention containing general provisions. Restrictions and prohibitions on particular weapons, such as blinding lasers, incendiary weapons, and mines are contained in protocols annexed to the Convention.

+ More

1980 Protocol on Incendiary Weapons

The 1980 Protocol III on Incendiary Weapons of the Convention on Certain Conventional Weapons restricts use of incendiary weapons as a means or method of warfare during armed conflict.

+ More